By Jack Sun | Updated October 7, 2026
Our company is based in Anping, Hengshui, Hebei, China, known as the wire mesh capital. Jack Sun has long worked in metal wire mesh weaving and industrial filter element manufacturing.
Quick definition: Sintered titanium fiber felt consists of titanium fibers joined at their contact points by sintering, creating an interconnected porous structure. This guide explains the use of pure titanium felt, with coated or uncoated surfaces, as a candidate titanium porous transport layer for the anode of a PEM water electrolyzer.
Selection requires checking pore structure, assembly contact and surface condition together. The description “pure titanium” alone does not establish compatibility with a particular electrolyzer’s efficiency or service-life requirements.
1. Position and Functions of the Porous Transport Layer
This guide is for design engineers evaluating electrolyzer materials and purchasing teams checking supply requirements. PEM means proton exchange membrane. The application discussed here is water electrolysis for hydrogen production; fuel-cell gas diffusion layer arrangements should not be transferred directly to an electrolyzer.
In a typical anode assembly, the porous transport layer sits between the anode catalyst layer and the flow field. The titanium fiber network provides an electronic conduction path. Its interconnected pores support water delivery to the reaction interface and the removal of oxygen produced there. The PTL also provides mechanical support in the assembled cell, and its suitability must be evaluated with the membrane electrode assembly and flow field.
Electrons travel through the metallic structure. Protons travel primarily through the membrane and associated ionomer. Water passage through titanium felt should therefore not be described as proton conduction through the felt. The anode consumes water and produces oxygen; hydrogen is generated at the cathode.
The PTL, catalyst layer and bipolar plate have separate duties. Pure titanium felt does not include a complete catalyst system, and its porous structure alone does not make it a universal replacement for a bipolar plate or a flow field.
2. Pure Titanium Felt: Advantages and Application Limits
Titanium-based porous materials are an established research and manufacturing route for PEM water electrolysis PTLs. A sintered fiber structure allows thickness, porosity and contact conditions to be considered during material selection. However, titanium can still passivate at its surface. Corrosion resistance and sustained low interface resistance require separate evaluation.
Research by Liu and colleagues describes titanium surface oxidation as a cause of increased resistance at the PTL/electrode interface.[1] Performance or durability results from a particular coated PTL cannot be treated as guarantees for a different coating specification or an uncoated part. Whether a subsequent surface treatment is required depends on the customer’s cell design and validation results.
“Uncoated” here means that no engineered functional coating has been applied. It does not mean that the titanium surface is free of a natural oxide film. Procurement specifications should still define cleanliness, storage, packaging and any preparation before assembly.
Projects specifying a precious-metal-coated PTL, a catalyst-coated electrode or a component qualified through a particular durability test should procure and validate against those requirements. We supply coated and uncoated titanium sintered felt according to the drawing and agreed surface requirements. Coating specifications and application suitability are confirmed for the intended component. Supply of a coated substrate does not by itself establish a complete catalytic electrode or a particular electrolyzer performance.
3. Titanium Porous Transport Layer Selection Parameters
Start with the flow field, assembly space, operating conditions and acceptance targets. The following items form an engineering checklist; they are not universal optimum values for every electrolyzer.
| Item | What to specify or verify | Purpose |
|---|---|---|
| Material and surface | Pure titanium grade, material documentation, cleanliness and subsequent treatment | Define composition and delivered condition |
| Thickness and assembly | Thickness tolerance, measurement conditions, gasket fit and assembly compression | Distinguish free-state dimensions from assembled conditions |
| Pore structure | Porosity, pore-size distribution, connectivity and measurement method | Equal porosity does not imply equal transport behavior |
| Contact surface | Flatness, surface morphology and locally protruding fibers | Assess catalyst-layer contact and assembly risks |
| Transport properties | Permeability direction, test medium and test conditions | Distinguish in-plane from through-plane transport |
| Electrical contact | Interface resistance under specified clamping conditions and its change over time | Material conductivity cannot replace interface validation |
Porosity alone is not a reliable ranking criterion. Changing the pore volume also changes solid contact and support, while transport depends on pore connectivity, direction and flow-field geometry. Ernst and colleagues evaluated titanium fiber and powder PTLs with different flow fields, demonstrating why PTL properties and flow-field conditions should be assessed together.[2] Their sample results are not specifications for our products.
We supply pure titanium sintered felt. The published titanium fiber felt porosity range is 50–80%. This describes the supply structure range; it does not mean that every product in that range meets a particular PEM project’s requirements.
Our broader sintered metal fiber felt product series has an overall thickness range of 0.10–1.50 mm. The specific pure titanium model, thickness and tolerance require project confirmation. The overall series range should not be treated as a confirmed specification for every pure titanium felt product.
A filter’s nominal micron rating cannot be directly interpreted as the PTL’s actual pore size or used to predict electrolyzer performance. Specify the relevant pore-structure metrics and measurement methods. Filtration rating, bubble point and permeability describe different characteristics.
4. From Manufacturing Requirements to Delivery Acceptance
Manufacturing pure titanium fiber felt involves fiber preparation, laying, sintering and any required dimensional finishing. The laid structure, sintered connections and subsequent processing together determine the delivered material condition. Convert the delivery requirements into drawings and agreed acceptance items.
For sheet supply, define the outline, thickness, edge condition, surface requirements, measurement positions and packaging in the drawing or technical agreement. Checks for protruding edge fibers, loose fibers and local deformation need agreed acceptance rules based on the assembly. A general instruction such as “good surface” is insufficient.
| Acceptance item | Information to agree before delivery |
|---|---|
| Material identification | Titanium grade, applicable material documentation and batch identification |
| Outline and dimensions | Drawing, tolerances, measurement positions and acceptance rules |
| Thickness measurement | Measurement pressure, number of points and evaluation method |
| Edges and surface | Rules for protruding or loose fibers, local deformation and cleanliness |
| Structure and transport | Agreed indicators, test methods, medium and test direction where applicable |
| Packaging | Protection, cleanliness, identification and storage requirements |
Thickness measurements on porous material can depend on the measuring conditions. Results obtained under different pressures or sampling methods should not be compared without checking the methods first.
Separate material delivery acceptance from electrolyzer validation. Delivery checks address material, dimensions, structure and appearance. Cell validation evaluates polarization behavior, impedance and durability changes with specified membrane electrode assembly, flow field, clamping conditions, temperature, pressure and water supply. Neither an appearance photograph nor a single porosity value establishes long-term suitability.
5. Information for Design and Procurement
Prepare the following information before selecting a pure titanium felt sample:
- Application position: anode PTL or another defined position, including any subsequent surface treatment.
- Material and delivery condition: pure titanium grade, documentation, cleanliness and packaging.
- Drawing and assembly: outline, tolerances, thickness, gasket fit and contact-surface requirements.
- Structure: target porosity, pore-structure or permeability indicators, with measurement methods.
- Operation and validation: temperature, pressure, differential pressure, current density, clamping conditions and test targets.
- Supply and acceptance: sample quantity, production quantity, inspection items and acceptance rules.
For a new project, discuss the material and structural requirements before agreeing on samples and validation. For an existing drawing, check the delivery specification against that drawing. For replacement from an old sample, dimensions and observable structure can support discussions, but an old sample alone cannot recover its original surface condition or complete electrochemical performance.
To evaluate pure titanium sintered felt, share the drawing, assembly conditions and acceptance items. We first review the material and manufacturing requirements, then agree on samples and the next steps. See the titanium fiber sintered felt product page and sintered metal fiber felt product page for related supply information and the new energy industry application page for broader context.
6. Frequently Asked Questions
Can pure titanium sintered felt be used directly in every PEM electrolyzer?
No universal conclusion applies. Check structure, contact and surface condition, then validate under the particular cell conditions. Bare titanium is not automatically equivalent to a specified coated component.
Does uncoated titanium felt have no oxide film?
No. The absence of an applied engineering coating is different from the absence of a natural oxide film. Define the delivered surface condition and any preparation required before assembly.
Is higher porosity always better for a PTL?
No. Evaluate porosity together with pore connectivity, contact conditions, thickness, support and the flow field. One percentage does not establish the best material.
Can a filter micron rating be used to select a titanium PTL?
Not directly. A nominal filtration rating is not an electrolyzer performance metric. PTL procurement needs relevant requirements for pore structure, contact and transport.
Conclusion
Selection of pure titanium sintered felt should result in verifiable specifications: defined material and delivery condition, pore structure compatible with the assembly, and appropriate evidence for surface and electrical behavior. Those checks provide a practical basis for sample evaluation and purchasing decisions.
Technical References
- Liu, C., Carmo, M., Bender, G., et al. Performance enhancement of PEM electrolyzers through iridium-coated titanium porous transport layers. Electrochemistry Communications, 97 (2018), 96–99. Used here to explain passivation and interface resistance; coated-sample performance is not a guarantee for uncoated felt.
- Ernst, M. F., Schriever, C., Schramm, C., et al. Correlating Flow Field Geometry and Porous Transport Layer Properties for Efficient PEM Water Electrolysis. Journal of The Electrochemical Society, 173 (2026), 114501. Used to support evaluating PTL properties with the flow field.
